Underground and submersible junction bus connectors are widely used in electrical power distribution systems. One type of such connector is offered under the designation SWEETHEART® by Homac Mfg. Company of Ormond Beach, Fla., the assignee of the present invention. The SWEETHEART® connector is a cast or welded aluminum connector including a bus, or bar, portion and a series of tubular posts extending outwardly from the bus portion. The posts have an open upper end to receive one or more electrical conductors. A threaded bore is provided in the sidewall of the post, and which receives a fastener to secure the electrical conductor within the upper end of the post. An insulating coating is provided on the lower portion of the posts and bus of the connector. In addition, EPDM insulating sleeves may be used to provide waterproof seals for the posts. U.S. Pat. Nos. 6,347,966; 6,345,438 and 6,262,567 disclose various embodiments of such bus and post connectors.
Homac also manufacturers a RAB series of “Flood Seal”® Rubberized Aluminum Bar connectors suitable for direct burial, handhole or pedestal applications. The RAB connector includes a generally rectangular aluminum body having a plurality of spaced apart cable-receiving passageways therein. These cable-receiving passageways are blind holes, that is, they extend inward, but do not extend fully through the connector body. The blind hole is useful to provide sealing at the lower end of the connector body for the later molding of the rubber insulating cover.
The connector body also has a fastener-receiving passageway intersecting each cable-receiving opening. A fastener is provided in each fastener receiving passageway. Each fastener comprises a blunt end for bluntly contacting a corresponding insulation-free cable end. In particular, the blunt end may be a ball bottom screw end that helps break up aluminum oxides of the insulation-free cable end to ensure better electrical contact.
As the name states, the RAB connector includes a rubber insulating cover over the connector body. The insulating cover includes integrally molded inlets for both the cable-receiving openings and fastener-receiving openings. An insulating boot, such as a cable size adaptor or Rocket may be provided for the cable-receiving inlet, and a sealing cap may be received over the screw in the fastener-receiving inlet. Unfortunately, with less experienced labor crews, it is possible that a cable end may not be fully seated in its blind hole. Thus, even if the fastener initially presses partially against the cable end, this connection may work lose as the RAB connector is subsequently repositioned.
U.S. Pat. No. 6,688,921 to Borgstrom et al. discloses a connector similar to the Homac RAB series connector. In place of EPDM, the patent uses a thermoplastic elastomer (TPE) that combines the properties of thermoplastic with the performance characteristics of a thermoset rubber. The use of TPE enables the molding to further form sealing plugs and cable size adaptors attached to the cover with respective tethers. The connector also includes blind cable-receiving passageways, and is thus also susceptible to less reliable connections if the cable ends are not fully seated.
Michaud Electrical Equipment of France offered an insulation displacing connector (IDC) including a generally rectangular connector body, and transverse cable-receiving and fastener-receiving passageways. More particularly, the connector body included a backwall having a pattern of sharp ridges thereon to pierce the insulation on the cable end as the end of the fastener engages and presses against the cable end from the opposite side. To be sure the cable end is fully pressed onto the sharp ridges, a plastic viewing window is provided opposite the inlet of the cable-receiving passageway. Accordingly, an installer can view the cable end to be sure the insulation has been pierced. The window is adjacent the rubber cover. Unfortunately, the Michaud IDC device is likely to leak at the window since the seal is only a mechanical seal. In addition, insulation displacement technology may not be suitable for larger cable sizes with thicker insulation coverings.
The Borgstrom et al. '921 patent discloses an integrally formed tether or strap between a removable fastener inlet closure cap and a fastener inlet. The tether is relatively narrow and weak, thereby discouraging gripping of the tether to facilitate positioning of the cap. Moreover, the integrally formed tether requires a fairly complicated and expensive mold so that it can be formed along with the insulating cover and other components as described in the patent.